For improving of the efficiency of multi-stage centrifugal pumps (ESPs) in the presence of free gas at the intake different technologies and design techniques are used: the appltcation of dispersants, gas separators, ‘tapered’ pumps, impellers of special designs, pump-ejector systems and other methods, one of which is the installation of the ejector in the ESP inlet.
In this paper we investigated regularities of ESP operation with an upstream gas-liquid ejector (LGE) on the gas-liquid mixtures (GLM) water – gas low foaming ability, simulating the conditions of watered oil and gas wells. The bench facility and the method of research were created, which allow to obtain the characteristics of submersible multistage centrifugal pumps on GLM, depending not only on the gas content, the pressure at the entrance, the pump operation mode, but also on the dispersion of the mixture in a wide range of regime parameters. For the first time the ESP characteristics were received which depending on the dispersion of the GLM created using LGE, in a wide range of heads and delivery rates. The research of ESP characteristics with upstream ejector at low foaming liquid mixture water – gas, to show the influence of various parameters and design LGE at the pump, were performed. With increasing pressure at the entrance to the pump effect of the gas on ESP performance decreases, and with an increase in gas content and the average diameter of the bubbles above a certain values - increases. The pump characteristics on GLM bent down in the left side. It was found that the strongest influence on the size of the bubbles has a gas content of the mixture. With its increase an average diameter of the bubbles is growing and this kind of dependence is determined by the layout of the flow part of LGE. Increased pressure has a positive effect on the dispersion of GLM, the average size of the bubbles is reduced, the stability of the dispersion system is increased. The deterioration of pressure-capacity parameters of ESP operation is enhanced by increasing the average diameter of the bubbles over 0.9-1.2 mm.
